1. Field of the Invention
The present invention relates to an image forming apparatus and a computer readable medium storing a program.
2. Description of Related Art
Conventionally, in some image forming apparatuses, a heater which is a heating unit is not provided on the pressing roller side from the viewpoint of energy saving.
However, sheets which are recording media to be used in an image forming apparatus have various kinds such as a thin paper, a rough paper, a coated paper and a thick paper. It is necessary to control the temperature of the pressing roller to maintain the quality of image formed on these papers.
Therefore, there is an image forming apparatus which does not perform a temperature control between sheets (hereinafter referred to as “sheet interval”) and which heats the pressing roller in a sheet interval and adjusts the temperature of the pressing roller to suppress the curling of a sheet and an improper fixing (refer to JP 2007-065313A).
However, in the image forming apparatus described in JP 2007-065313A does not turn on a heater in a sheet interval to perform temperature control, in a configuration in which a fixing belt is stretched around a fixing roller and a heating roller having a heater, there is a problem that the temperature of the fixing belt fluctuates and results in a defect such as uneven brightness.
Also, even in a configuration in which a fixing roller and a pressing roller are directly pressed to each other, since the temperature control by turning on a heater is not performed in a sheet interval, there is a problem that a pressing roller is heated more than needed and the temperature of the pressing roller is not able to properly controlled because degree of heat propagation to the pressing roller through a conveyed sheet is different depending on the type of a sheet (for example, a thin sheet or the like).